Brett Zongker, Eric Tucker and Lolita C. Baldor, AP

UPDATE: 7:01 a.m.

WASHINGTON - An employee at a defense contractor used his pass to get into the Washington Navy Yard and went on a deadly shooting rampage Monday, spraying bullets in the hallways and firing from a balcony on workers in an atrium below. Thirteen people were killed, including the gunman. ...

The motive for the attack - the deadliest mass shooting on a military installation in the U.S. since the tragedy at Fort Hood, ...